Johnny Morgan, Hollier, Clayton A. | 9/13/2013 2:00:37 AM
BATON ROUGE, La. – Now that the Louisiana corn harvest is nearly complete, growers have been given a few ways to decrease the chance of the Goss’s wilt bacteria overwintering in their fields.
LSU AgCenter plant pathologist Clayton Hollier said corn growers can burn and bury corn crop residue to decrease their chances of having a widespread outbreak of the disease next year.
“Since the bacterium survives in infested residue, any type of tillage operation that buries residue to encourage decomposition may be effective in reducing the rate of new infections,” Hollier said.
Rotating out of corn into other crops such as soybeans or small grains will help reduce primary inoculum sources in corn residue, he said.
“On June 18, samples were taken from corn fields in Madison Parish that had both classic leaf symptoms and disease spread pattern of Goss’s wilt in the corn hybrid DK 6694,” he said.
Since that time the disease also has been confirmed in East Carroll, West Carroll and Tensas parishes.
“In addition to corn, other hosts for the pathogen include green foxtail, shatter cane and barnyard grass,” he said “Therefore, weed control may also be important for disease control.”
LSU AgCenter county agent R.L. Frazier in Madison Parish has been collecting data on the extent of the loss from Goss’s wilt with yield monitors.
Hollier said the disease causes problems in a circle sometimes 50 feet in diameter.
“The plants affected in the circular pattern will be the most damaged, with losses ranging from 100 percent in the ‘epicenter’ to minor, if any, losses at the edge of the circle,” Hollier said.
It’s not known how the disease was introduced into Louisiana – whether through seed or wind. But it’s never been this far south before, Hollier said.
The environmental conditions in Louisiana are expected to be harsh on the bacteria because it is not native, Hollier said. “Overwintering survival is not expected with tillage and decomposition of residue. But we are dealing with nature, so there are no guarantees.
“If you had the disease in your corn crop this year, burning the residue is a general recommendation, but I would go a step further and bury it also,” Hollier said. “Burying the residue will kill the pathogen.”Johnny Morgan
The LSU AgCenter and the LSU College of Agriculture